Machines for spraying asbestos or the like



March 3, 1964 Filed May 25, 1959 B. MOODY 3,122,792

MACHINES FOR SPRAYING ASBESTOS OR THE LIKE 4 Sheets-Sheet l March 3,1964 B. MOODY 3,122,792

MACHINES FOR SPRAYING ASBESTOS OR THE LIKE Filed May 25, 1959 4Sheets-Sheet 2 Inventor B P/Q- h M 00 B Attorney;

March 3, 1964 B. MOODY MACHINES FOR SPRAYING ASBESTOS OR THE LIKE FiledMay 25, 1959 4 Sheets-Sheet 5 f 2 H w 4 Inventor 871' Meet,

ttorneys March 3, 1964 B. MOODY 3,122,792

MACHINES FOR SPRAYING ASBESTOS OR THE LIKE Filed May 25, 1959 4Sheets-Sheet 4 I n ventor 57th Mood,

6 E q Attorneys United States Patent C) 3,122,792 MACHINES FOR SPRAYINGASBESTO GR THE LIKE Bryan Moody, Clayton-le-Woods, Charley, England,assignor to I. W. Roberts Limited Filed May 25, 1959, Ser. No. 815,486Claims priority, appiication Great Britain May 30, 1958 9 Claims. (Cl.19-93) This invention relates to that kind of machine by which asbestosor other mineral fibres are formed into a suspension and sprayed onto asurface to form a coating on it as insulation against heat and sound.

In the operation of machines of this kind the fibres are commonlysupplied to a hopper, and they should be extracted from this andconveyed forwards at a uniform rate. In practice there is considerabledifiiculty in doing this.

An important object in this invention is to provide an improvedapparatus for extracting asbestos fibres from a hopper and conveyingthem onwards.

The essence of the present invention is the provision at the base of thehopper of two or more toothed rollers arranged so that when they arestationary they essentially support the mass of fibres in the hopper,but when they rotate they draw the fibres downwards. In practiceasbestos and similar fibres fed to a machine from sacks are in the formof clots or lumps, and even though the toothed rollers may exert acombing action on the fibres as they move downwards it is found inpractice that clots tend to pass through them. These rollers mayadvantageously be a central toothed roller and two lateral toothedrollers, the latter moving at faster peripheral speeds to exert acombing action on the fibres.

Means are provided for breaking up clots of fibre that have passedbetween the rollers. These means may in clude the rollers or may bewholly separate from them.

In one convenient form of construction a supporting surface is providedbelow the rollers, preferably of inverted shallow V shape, to serve twopurposes. In practice there are not only clots of fibre but also smallerflocks which, when the toothed rollers are stationary, may pass betweenthem, and on passing tend to clog the apparatus and make it difiicult tostart it into motion. The supporting surface below the rollers retains alarge number of such flocks. Secondly the supporting surface may withadvantage be arranged only a short distance below the rollers so thatclots of fibre cannot easily pass between the supporting surface and therollers without being struck by the teeth of the rollers and broken up.

The means for breaking up clots may also comprise a rotary drum havingvanes which strike any clots of fibre and tend to break them. Both thesemeans of breaking up clots may be provided in a single machine.

Another device for breaking up clots of fibre that have passed betweenthe toothed rollers comprises a rotary disc mounted about a verticalaxis within a casing, the fibre (including any clots) falling on thisdisc and being flung radially into contact with the casing and broken byimpact both onto the disc and in turn onto the casing.

In all cases the rate of delivery of the fibre by the toothed rollersshould be less than the rate at which the conveying means can carryfibre to a spraying fan or than the fan can receive fibre withoutchoking. There fore in operation there is always some void space belowthe supporting surface and between it and the part by which the fibre isnext engaged.

Machines according to the invention will now be shown by way of examplewith reference to the accompanying drawings in which:

FIGURE 1 is a part sectional and part elevational view around thecylindrical surface.

3,122,792 Patented Mar. 3, 1964 ice of one machine, various drivingconnections being omitted for the sake of clarity;

FIGURE 2 is a section on the line IIII in FIGURE 1 with a drum shown inelevation;

FIGURE 3 is a partly diagrammatic side elevation of the same machine;

FIGURE 4 is a plan of this machine;

FIGURE 5 is a side elevation of another machine; and

FIGURE 6 is a section through a smaller machine.

The machine shown in FIGURES 14 comprises a hopper 1 of rectangularsection, tapering from wide at the top to narrow at the bottom. Thesides 2 and 3 taper continuously but the sides 4 and 5 are vertical atthe top. Three rollers 6, 7 and 8 having teeth in the form of spikes 9are mounted rotatably and horizontally in bearings in opposite wallsnear the bottom of the hopper. Each roller is hollow and the spikes 9mostly project radially from it, but project at an angle near the end soas to ensure that some spikes (9a) work close to the walls of thehopper. Sprockets 10, 1t), 10" on shafts projecting outside the hopperfrom corresponding ends of each roller are interconnected by a chaindrive 11. The sprockets on rollers 6, 8 and 7 have 12, 24 and 36 teethrespectively so that the speeds of rotation of these rollers are alwaysin the ratio 3:2:1.

If the hopper is filled with asbestos fibre of the consistency in whichit is found in a bale compressed for transporting and the fibre isforced down into the hopper so that it comes into contact with thespikes on the roller, revolution of the rollers will then cause thespikes to tear into the fibre, exerting a combing action on it, and pullit downwards. The tearing eifect of the rollers on the fibre pulled downgreatly depends on the ratio of the speeds of rotation of adjacentrollers. Inevitably some clots of as bestos pass between the rollers.Moreover when the rollers are stationary small flocks of asbestos maypass between them. Below the rollers there is a stationary sup portingsurface 12 of inverted V shape in cross section, the V being shallow asshown in FIGURE 1. This surface 12 is formed by sheet metal spanning thesides of the hopper and it prevents clots drawn down between the rollers6 and 7 from falling directly onto the drum 14. Similar clots that passbetween the rollers 7 and 8 are trapped between the right-hand side ofthe surface and the spikes on the roller 8. In addition when theapparatus is temporarily not in use, e.g. because the operator hasstopped it for a short time, small flocks of asbestos that may fallbetween the rollers descend onto the surface 12 and are largely retainedthere. In the absence of the surface they would tend to move furtherdownwards and thereafter, by clogging the parts beneath the surface 12,make it difficult to start the machine again.

Below the surface 12 there is a cylindrical drum 14 which carries radialvanes 16 running parallel to the axis In addition each end of the drumcarries vanes extending radially from the axis to the cylindricalcircumference as shown at 15. The drum 14 rotates so that the vanes 16catch the falling fibre and fling it towards a metering cylinder 17mounted to rotate about a parallel axis and in the same direction.Conveying spikes 18 inclined to the axial planes of the cylinder projectfrom the curved surface thereof, and pick up the fibre gathered by thevanes 16 when this fibre is brought round and onto the cylinder 17. Thefibre picked up by the cylinder is carried round by it to the pointwhere it is stripped from it by a carded stripping brush 19 rotating inthe opposite direction to the cylinder at a higher surface speed. Thestripped fibre is now sucked as a suspension through a tube 20 by a fan21 and so to a spraying nozzle not shown. A steel comb 22, fixedadjustably to the walls of the casing 23 in which the metering cylinderand associated parts are housed, combs the fibre as it is \K N p arevolved on the metering cylinder and just before it is removed by thestripping brush, and by evening it makes its removal easier.

All rotating parts are driven by a variable speed electric motor 24.Some of the driving connections are omitted in FIGURE 1, and theseconnections are best shown in FIGURE 3. A sprocket 25 on the motor shaftdrives a sprocket on the shaft of the cylinder 17 by a chain 26, andthis drive is transmitted to sprockets on the shafts of the brush 19 anddrum 14 by a chain 27 and a crossed belt 28 respectively. The preferredspeeds of rotation of therotating parts 19, 17 and 14 are 466, 12 and235 rpm. respectively, the size of the pulleys being chosen to givethese speeds and internal reversing gearing (not shown) Within the drum17 causing it to rotate in the same direction as the cylinder 14 eventhough the belt 28 connecting them is crossed. Another chain drive 29connects another pulley on the shaft of the cylinder 17 with a gearbox30 and this drive is transmitted to the shaft of the roller 8 by meansof a chain 31. By means of the gearbox 30 the'speeds of rotation of therollers 6, 7 and 8 may be altered without alteration of the speeds ofrotation of the parts 19, 17 and 14 or of the motor 24 and vice versa. 7In the construction shown in FIGURE there are a hopper 1, rollers 6, 7and 8, a supporting surface 12, and a vaned drum 14 which areessentially the same in construction and operate in the same Way as inthe machine shown in FIGURES 14. The vaned drum fiings the fibre itcollects to an endless conveyor belt 52, supported at either end byrollers 33, 33'. Spikes 34 projects from the face of the belt and fibrecaught by the belt off the drum 14 is raised to the top of the beltwhere a stripping brush 35, Working like the brush 19 already described,removes it from the conveyor, the fibre then falling into the suctioninlet of a fan 36 which delivers the fibre to a nozzle. An

evener brush 37 revolves close to the top of the belt and ensures thatthe belt is carrying no thicker a layer of fibre than is wanted by thetime it reaches the stripping brush. The evener brush acts to skim thesurplus fibre from the belt and fling it backwards.

In the construction shown in FIGURE 6, three spiked rollers 38 work atthe bottom of a small hopper 39. The relative speeds of rotation ofthese rollers, and the way in which they are driven are similar to thecorresponding features of the rollers 6, 7 and 8 already described.Fibre pulled from the hopper by the rollers falls onto a disc 40 rotatedabout a vertical axis, and having radial ribs 41 projecting from itsupper surface. The disc flings the fibre centrifugally outwards as asuspension in air, and this suspension is sucked downwards through theannular gap 42 surrounding the disc by a fan impeller 43 carried by avertical shaft 45 which also carries the disc 40. The shaft 45 is drivenby a motor 46, and fibre received by the impeller 43 is delivered by itthrough an outlet 44 to a spray nozzle.

. I claim:

1. In a machine for forming asbestos or other mineral fibre into asuspension in air and spraying it onto a surface, the combination of ahopper for the fibre, means bounding a space below the hopper, at leastfirst and second toothed rollers laterally offset from one another andmounted within the lower part of the hopper above said space to turnabout parallel substantially horizontal axes, said rollers being adaptedto engage the fibre and draw it downwardly, a third toothed rollermounted within the lower part of the hopper to turn about asubstantially horizontal axes parallel to, higher than and verticallybetween the axes of the said first and second rollers, means to drivesaid first, second and third rollers, said driving means driving saidthird roller at a lower peripheral speed than said first and secondrollers for loosening asbestos to pass to the first and second rollers,the paths of the tips of the teeth of the first, second and thirdrollers being spaced apart in directions perpendicular to the axes ofthe rollers, the three rollers together serving when they are stationaryto support the mass of fibres in the hopper, and means for breaking upclots of fibre that have passed the rollers.

2. Machine according to claim 1 in which the means for breaking up theclots include a supporting surface arranged only a short distance belowthe rollers so that clots of fibre cannot easily pass between thesupporting surface and the rollers without being struck by the teeth ofthe rollers and broken up.

3. Machine according to claim 1 in which the means for breakin up clotsinclude a rotary drum having vanes adapted to strike and break clots offibre.

4. Machine according to claim 1 in which the means for breaking up theclots comprise a casing and a rotary disc mounted about a vertical axiswithin the casing, to receive the fibre (including any clots) fallingfrom the rollers and fling it radially into contact with the casing.

5. Machine according'to claim 4 which includes a fan exerting suction onthe space between the disc and the casing and mounted below and coaxialwith the disc.

6. Machine according to claim 4 in which the disc has radial ribs on itsupper surface.

7. Machine according to claim 1 including a fan and conveyor means fortransferring fibre from beneath said means for breaking up clots offibre towards said fan.

8. Machine according to claim 7 in which the conveyor means is a rotarydrum with a spiked surface.

7 9. Machine according to claim 7 in which the conveyor means is aspiked belt.

References Cited in the file of this patent UNITED STATES PATENTS469,560 Groom Feb. 23, 1892 690,614 Rodgers Jan. 7, 1902' 830,646 DavisSept. 11, 1906 959,746 Humason May 31, 1910 1,769,669 Wuest July 1, 19302,646,381 Duvall July 21, 1953 2,764,013 Harrell Sept. 25, 19562,883,709 Deems et al. Apr. 28, 1959

1. IN A MACHINE FOR FORMING ASBESTOS OR OTHER MINERAL FIBRE INTO ASUSPENSION IN AIR AND SPRAYING IT ONTO A SURFACE, THE COMBINATION OF AHOPPER FOR THE FIBRE, MEANS BOUNCING A SPACE BELOW THE HOPPER, AT LEASTFIRST AND SECOND TOOTHED ROLLERS LATERALLY OFFSET FROM ONE ANOTHER ANDMOUNTED WITHIN THE LOWER PART OF THE HOPPER ABOVE SAID SPACE TO TURNABOUT PARALLEL SUBSTANTIALLY HORIZONTAL AXES, SAID ROLLERS BEING ADAPTEDTO ENGAGE THE FIBRE AND DRAW IT DOWNWARDLY, A THIRD TOOTHED ROLLERMOUNTED WITHIN THE LOWER PART OF THE HOPPER TO TURN ABOUT ASUBSTANTIALLY HORIZONTAL AXES PARALLEL TO, HIGHER THAN AND VERTICALLYBETWEEN THE AXES OF THE SAID FIRST AND SECOND ROLLERS, MEANS TO DRIVESAID FIRST, SECOND AND THIRD ROLLERS, SAID DRIVING MEANS DRIVING SAIDTHIRD ROLLER AT A LOWER PERIPHERAL SPEED THAN SAID FIRST AND SECONDROLLERS FOR LOOSENING ASBESTOS TO PASS TO THE FIRST AND SECOND ROLLERS,THE PATHS OF THE TIPS OF THE TEETH OF THE FIRST, SECOND AND THIRDROLLERS BEING SPACED APART IN DIRECTION PERPENDICULAR TO THE AXES OF THEROLLERS, THE THREE ROLLERS TOGETHER SERVING WHEN THEY ARE STATIONARY TOSUPPORT THE MASS OF FIBERS IN THE HOPPER, AND MEANS FOR BREAKING UPCLOTS OF FIBRE THAT HAVE PASSED THE ROLLERS.